1. Field of the Invention
The present invention relates to a technology for depositing a film on a substrate by carrying out plural cycles of supplying in turn at least two source gases to the substrate in order to form plural layers of a reaction product.
2. Description of the Related Art
As a film deposition technique in a semiconductor fabrication process, there has been known a process, in which a first reaction gas is adsorbed on a surface of a semiconductor wafer (referred to as a wafer hereinafter) and the like under vacuum and then a second reaction gas is adsorbed on the surface of the wafer in order to form one or more atomic or molecular layers through reaction of the first and the second reaction gases on the surface of the wafer, and such an alternating adsorption of the gases is repeated plural times, thereby depositing a film on the wafer. This technique is called Atomic Layer Deposition (ALD) or Molecular Layer Deposition (MLD) and advantageous in that the film thickness can be controlled at higher accuracy by the number of times of alternately supplying the reaction gases, and in that the deposited film can have excellent uniformity over the wafer. Therefore, this deposition method is thought to be promising as a film deposition technique that can address further miniaturization of semiconductor devices.
As a film deposition apparatus to carry out such a deposition method, a single-wafer deposition apparatus having a shower head at a top center portion inside a vacuum chamber is used, and a deposition method using such an apparatus has been under consideration. When such a deposition chamber is used, it takes a long time to purge the reaction gases with a purge gas, resulting in an extremely long process time because the number of cycles may reach several hundred. Therefore, a deposition method and an apparatus that enable high throughput are desired.
Under such circumstances, a film deposition apparatus in which plural substrates are arranged on a turntable along a rotation direction of the turntable in a vacuum chamber has been proposed in Patent Documents 1 through 8.